Crop harvesting headers which use rotary cutters in replacement for the more conventional sickle knife systems have been available for many years. It is well known that such rotary cutters include a cutter bar or gear train which provides the main structural and drive communication components of the cutter. The cutter bar provides a series of longitudinally spaced vertical drive members each of which drives a respective one of a plurality of cutting disks at spaced positions along the cutter bar. The disks are mounted for rotation about a vertical axis standing upwardly from the cutter bar. The disks carry at a point on their outer edge a plurality, generally two, of flail type blades which rotate with the disk around the vertical axis in a cutting action.
The construction of the cutter bar itself including the suitable gear train is well known and a number of different designs are available which can be used by a person skilled in this art.
Examples of such rotary type cutters are shown in the following documents.
U.S. Pat. No. 5,272,859 (Pruitt) issued Dec. 28, 1993 discloses a mower/conditioner including a cutter bar and rotating disks feeding to a rear discharge opening containing a pair of conditioning rollers. The outermost disk carries a generally cylindrical impeller in the form of an upright cylindrical cage. In front of the discharge opening is a series of disks arranged in counter-rotating pairs.
US published Patent Application 2005/0126142 (Rosenbalm) assigned to Deere which discloses a cage type impeller where the bottom disk of the impeller is formed as a frusto-conical member converging upwardly and inwardly to the cage bars.
U.S. Pat. No. 5,463,852 (O'Halloran) issued Nov. 7, 1995 and U.S. Pat. No. 5,433,064 issued Jul. 18, 1995 (Schmitt) assigned to Hay and Forage Industries of Hesston both show a construction of such a rotary cutter system in which there is a series of the cutter disks at spaced positions across the cutter bar with, at each end, two of the cutter disks extend beyond a central area in front of a discharge opening. In this arrangement the two end disks are driven by a mechanical drive system. The two end disks each carry a rotary transfer element in the form of a series of posts arranged at the periphery of a cylinder surrounding a vertical axis standing upwardly from the disk. The transfer elements act to carry the crop material which is cut by the disks inwardly toward the discharge opening. A conventional crop conditioner in the form of a pair of counter-rotating rollers is mounted across the crop discharge opening.
U.S. Pat. No. 6,158,201 (Pruitt) issued Dec. 12, 2000 also assigned to Hay and Forage Industries discloses a modification to the above 852 and 064 patents of HFI where a crop transport roller is added in the crop discharge opening and is arranged to carry crop up to the nip of the conditioner rollers.
U.S. Pat. No. 5,768,865 (Rosenbalm) issued Jun. 23, 1998 assigned to Deere and Company discloses a rotary cutter system which has two end disks outboard of the central discharge opening with a conditioner arranged at the discharge opening for receiving the cut crop and providing a conditioning action. The conditioner can be either of a flail type or of a fluted roller type.
U.S. Pat. No. 4,809,488 (Neuerburg) issued Mar. 7, 1989 assigned to Kuhn discloses a rotary cutter system which has a frusto-conical cage as the impeller on an end disk where a drive shaft extends into the top of the cage.
EP 358,045 (Ungruh) assigned to Niemeyer Sohne GmbH published Nov. 3, 1993 discloses a mower which has at least four cutting disks arranged in two pairs rotating in the same direction and feeding to the center. Above each disk carries a cylindrical impeller which has a surface running inwardly to carry the crop towards the centre. In the region between each of the disks of each pair is a further cylindrical impeller which assists in transporting the crops to the centre.
German 32 24 170 (Mortl) published Dec. 29, 1983 discloses a header having a discharge opening behind the outermost cutters of a group which includes four cutters. The group is arranged in two pairs with each pair rotating in opposite directions. Thus the outer cutter of the group rotates inwardly. Outboard of this cutter is provided a further cutter which also rotates inwardly as shown by the arrows. This reference also includes a pair of impellers, each mounted on a respective one of the two outer cutters which act as a conveying device for carrying the crop inwardly. The impeller is generally an upwardly tapered element of triangular cross-section.
EP 0 016 661 (Maier) published Nov. 12, 1986 and assigned to Deutz Fahr discloses a cutter bar formed by a series of cutting disks where the end two disks at one end each carry a respective cylindrical impeller for carrying the cut crop to a discharge opening where there is located a conditioner.
German 35 01 133 (Schulze-Selting) published Jul. 17, 1986 also assigned to Deutz Fahr discloses a cutter bar formed by a series of cutting disks where the end disk at one end carries a respective cylindrical impeller for carrying the cut crop to an opening and there is provided an intermediate suspended impeller over the next disk where the suspended impeller is frusto-conical.
U.S. Pat. No. 4,330,982 (Vissers) issued May 25, 1982 and assigned to Multinorm discloses a series of rotary cutters with a pair of conditioning rollers which extend transversely or laterally across the mower narrower than the cutting zone and located in a discharge opening. A roller defines a portion or surface that moves upwardly and rearwardly from the cutting plane to the nip to convey the crop cut by the cutting disks toward the nip.
U.S. Pat. No. 2,906,077 (Hale) issued Sep. 29, 1959 discloses conditioner rollers in front of which is mounted a rotating roller which rotates to feed crop upwardly and rearwardly into the nip. Forwardly of the roller is located a sickle blade type cutter.
U.S. Pat. No. 3,014,324 (McCarty) issued Dec. 26, 1961 discloses a pair of conditioner rollers feeding into a nip therebetween. A roller is located in front of and below the nip of the conditioner roller and rotates in a direction to feed crop into the nip.
Canadian 2,166,671 (Savoie) published Apr. 6, 1997 discloses a disc cutter and a conveyor roller which feeds into the nip between a pair of conditioning rolls located in a discharge opening behind and narrower than the cutter.
From the above prior art patents, it will be noted that it is well known and widely used that each of two outermost disks carries a respective impeller body carried on the disk and driven by the disk about a common generally upright axis. These impeller bodies or members act to carry the crop as it is cut inwardly toward the discharge opening so that the crop can better enter the discharge opening with less chance of blocking or collecting in the area in front of the disks or within the discharge opening.
In many cases the discharge opening contains a conditioner for engaging and breaking or fracturing the crop to improve drying action as the swath is left in the field. Such conditioners can be of a number of different types but one common type uses a pair of fluted rollers which form a nip so that the crop is bent as it passes between the flutes.
Where a crop conditioner is used, a transfer roller is commonly used to lift the crop from the cutting zone to the nip of the conditioner rollers.
The different types of impellers used commonly at the outer cutting disks include drums which are of closed outer wall and cages which are formed of bars at angularly spaced positions around the axis. In most cases the impellers are cylindrical so that the cross section of the impeller is constant along the height of the impeller. In other cases the impeller is tapered so that its diameter decreases as the height increases so that it is either frusto-conical if circular in cross-section or frusto-pyramidical if of square or triangular cross section.
In many cases the impellers are carried on and driven by the disks but in addition intermediate impellers, which are located at a position which is not aligned with one of the disks, can be supported and driven from above as a suspended or hanging impeller. These hanging impellers have the same shapes and construction, that is cylindrical or tapered, as the standing impellers at the disks.